Process for forming decorative sheeting



D. [7, 1943; M, L PIKER 2,336,292

PROCESS FOR FORMING DECORATIVE SHEETING Filed Feb. 4, 1941 MAURICE L PIKER INVENTOR M w AT ORNEYS lines and streaks in I Patented Dec. 7,

PROCESS FOR 2.336.292 FORMING nnoommvn. snnn'rmo.

Maurice L. Plker, mam, N. Y.,';assignor to i Eastman Kodak Company, Roch ter, N. 2.. a

corporation New-Jersey V Application February 4, 1941, se ial No. 371,351

This inventionrelates to cellulose derivative sheeting. and more particularly an improved method of applying and fixing a coating thereon.

As is wen known, cellulosederivative sheeting has found wide use in numerous fields which formerly employed paper. As illustra tive, without limiting the invention, one of these fields inwhich cellulose ester sheeting has made great inroads and has had considerable popularity is that of paper lampshades.

- Some of the advantages possessed by the cellulose derivative sheeting over paper are that 13 Claims. "(01. 111-63) Entirely different from these factors, and in addition to them, is the matter of controlling quality of the coating by a choice of solvents.

As is described more fully in the following paragraphs, one of the preferred methods employed inapplying pigmented ,coating solutions or subs to the cellulose derivative sheet includes directing a stream of air against'the coating. 1-

found if the solvents of the .g.pplied sub are es-' sentially low boiling, the driedecoa-ting reflects the fact that the drying air is not always uniform in velocity or in direction. The pigment the ester sheeting maybe washed, it has no fibrous surface to which dust tends to collect, it

" is tougher and more resistant to breaking. V Dyes and pigments may be incorporated in the cellulose derivative solution from which the sheeting is formed thereby dispensing with the need of printing colors on the paper, and it may be lacquered. By control of the dyes and pig-.

ments added to the solution from which the sheeting is formed variations from a' transparent to an opaque sheet may be produced. While the colored pigments and dyes may be incorporated'in the sheeting, per ,se, for example, by the method disclosed in Couch et al. Patent'2,039,708 of May 5, 1936, the coloring effect desired by different customers varies'considerably and, therefore, it is more economical to make the sheeting by a somewhat different process. a It was decided that greater economies could be made by forming an uncolored base sheet and then coloring this sheet with a colored overcoat in the color'desired by the purchaser. By such a method a large variety of tints and colors could be easily produced while employing only one composition for the supporting sheet.

The base sheetmay be made according to standard procedure such as by flowing a solution containing the cellulose derivative and plasticizer onto a moving smooth surface andprogressively evaporating the solvent from the solution to form a thin, continuous sheeti The colored coating may be applied to this sheet with a bead applicator. In this device the sheet is passed across but out of contact with a rotating roll which transfers the coating solution from a supply in a pan to the sheet; the solution forming a "bead between the upper surface of the roll and the sheet.

In coating sheeting with a bead applicator there is :usually a problem of eliminating cross the coating. Cross lines and streaks may be functions of the mechanical equipment and are also functions, in some cases, of the solution being coated. In general, the best control for those caused mechanically is. in having smooth running equipment which-is free from vibration".

coating is-inclined to pile up in local areas, resulting inblotchinessor thicker deposits of sub, thereby giving darker color'in local areas. The

coatingalso tends-to deposit in more or less regular lines across the support in a pattern somewhat governed by vibration and air flow.

On the other hand, while the use of high boiling solvents in place i of low'boiling solvents f modifies the tendency of pigmented coatings to set' up due ,to uneven application, high boili s solvents have little quick t for the base itself. Accordingly, I found that the 'sub coating is not anchored firmly to the base I can be stripped therefrom very easily. The

adherence of the coating,.therefore, is less than that required for sheeting to be fabricated into I lamp shades.-

An object, therefore, of the present invention is a process "for uniformly coating pigmented and colored coatings onto cellulose derivative sheeting, which may among other uses be em- 'p oyed ,sheeting'with a pigmented and/or dyed coating which is in solution in a, solvent mixture con.-

taining relatively high boiling solvents. The

coating may be applied by a bead applicator apparatus which is pre'ferablymounted in a drying chamber through which air at an elevated temperature is passed. The solvent mixture containing the high boiling solvent is thus uniformly dissipated. from the coating solution leaving a smooth decorative coating on the sheeting. The adherence of this coating is to adheremore rather slight and to cause. it

solution which forms the course of the rotation of is removed by 'net2l.

around guide roll 24..

8 8 8,. -coating The path of the sheet is over guide rolls firmly, the coated sheet is treated'with a low boiling solvent or solvent mixture. This solvent has a strong and quick solvent action forthe coating and the I coating to the sheet. The solvent may also be applied by a' bead applicator apparatus similarly mounted in the drying chamber. 1 After curing the coating will tenaciouslyadhere to the base sheet. 1 I

In, accordance-with another feature of the invention the colored decorative layer may be anchored to the sheeting and at thesame time a protective overcoating for the decorative layer maybe applied. This may be done by adding .to the low boiling solvent or solvents a cellulose derivative whichon evaporation of the solvents will adhere to the decorative layer.

In accordance with still another feature of the From guide roll 3i thesheet passes into the adjacent drying chamber 32 whereit passes over sheet and thus anchors the invention the surface of the overcoating on the 1 decorative layer may be made either a matte surface or a glossy surface. If a matte surface is desired, a small amount of pigment may be the overcoating solution. If a incorporated in glossy-surface is desired the pigment maybe omitted in the overcoating solution.

The invention will be further understood by reference to the following detailed description and attached drawing which schematically shows the arrangement of apparatus preferably em- 7 ployed informing and coatingmellulosederiva- 30 tive sheeting,

As shown in the drawing positioned. A gas or air inlet flow into and around the drumv II in a clockwise direction and countercurrent to the path of the sheet II. The air leaves the chamber by outlet It. The cellulose deriva tive solution from-which the sheet is formed is introduced through conduit I! to hopper II.

the bottom of the hopper onto the slowly revolving drum H which is heated initial evaporation lution. As the solution on the drum ll is carried along its .meets the countercurrent air flow Q and further solvent is evaporated from the solution. The solvent is swept out of the chamber by the air through budget I. Somewhere in the drum vent has been expelled to permit the formation of a cellulose derivative sheet and this sheet l'l striping roll II and conducted over. guide roll it to the associated dry'ingcabi- Here the sheet I! is passed under guide roll 22 over guide roll 23 and under guide roll 24 A,bead applicator apparatus is positioned be-.

neath guide roll 24;

This apparatus comprises pan 25 and applicator 17011 28 which revolves partially immersed in to contact the sheet across the length of appli- 'cator; roll 26. The sheet thusbecomes coatedon its underside wlth'the coating which, in accord- 'ancewith the invention, is but superflciallyate sheet II. The sheet l'lprothetached to the base throughfthe drylng chamber, and f is dried thereon by solvent evaporation.

and under guide roll I.

sufficiently tocause of the solvents from the sogives a glossy or matte finish may simultaneously be added. Afterthi's operation the sheet passes through'the drying chamber over rolls 38 and 39,

under rolls 4! and 42, over rolls and 44 and Zunder roll 45 into drying chamber 52 where it may be further cured as it passes through the chamber on the guide'rolls' 46, ll, 48 and 49. The sheet I! then leaves the drying chamber ts. and is wound upon reel 5|. It will be noted 7 (that drying chambers 2!, 32 and 52 have air entry' ports 53, 54 and 55,and air exit ports 56, 51- and It will be understood that various types of cellulose derivative sheets may be made and coated in accordance with my invention. Cellulose there is an enclosed system for forming and coatlngscellulose deriva-- tive sheeting comprisingan' enclosed sheet-forming chamber ID in which a rotatable drum II is ll permits air to The solution flows through an elongated slot in u suflicient sol-' nitrate, cellulose acetate,'mixed esters suchas cellulose acetate propionate and cellulose acetate butyrate; cellulose ethers' such as methyl, ethyl,

and benzyl cellulose, may he the base for the sheeting." a

The following high boiling solvents may be employed. if desired, in preparingthe colored coating solution: v

:MethyI Cellosolve Methyl Cellosolve acetate Butyl Cellosolve Diacetone'alcohol Butyl alcohol Ethyl lactate Butyl lactate Amyl acetate Butyl acetate with these high boiling solvents I may employ 'one or more of the following low boiling solvents:

Acetone Ethyl acetate Methyl acetate Methyl alcohol Ethyl alcohol ,Ethylene dichloride 'Methylene dichloride As will be apparent from the above list of solthe decorative coating solu-,

tion'21. The applicator roll 28 is unlisted to be -iust out of contact with the sheet II as it p l s However, this' distance is, small enough to permit ahead of the solutionvents by high boiling solvents, I mean solvents having boiling points above 100 C. and in a range of approximatelyl25 to 200 C. By low boiling solvents I mean solvents which havea boiling point less than 100 C. and approximately .within the range of 40 to C.

7 Example 1 The invention may be illustrated with a cellulose acetate sheet containing as'plasti'cizer 32% diethyl phthalate based on theweightof the cellulose acetatefi Such asheet may be formed by v putting the ester and plasticizer in solution in I about 400 parts of acetone. .This solution is coated onto the drum II and anintegral transparent sheet is formed. It may be stripped from the and passed through the drying chamber 2|.

Methyl alcohol tatesheeting is the following:

Example 2 If it is desired form a white translucent coating on this cellulose acetate sheet a solution con- I taming:

L V 4 "Per cent Cellulose nitrate 2 .3- 35. Acetone 30 Methyl Cellosolve, 16

Titanox (T102) Butyl almhnl may be placed in the first bead'applicator in cabinet 2|. The solution is maintained at approxi- *mately 60 F. by means such as a hotwater coil.- not shown. The atmosphere in this cabinet is maintained at about 135? F. by air being passed into thecabinet at about this temperature. The

pigmented coating superficially attached itself to thecellulose acetate sheet and excess solvent is driven off in chamber 2|. From chamber 2| the sheet now coated with the pigment, enters heating chamber 32 and the pigmented side of sheet ll passes over the bead applicator roll "and a thin layer of anchoring" solvents is applied to the pigmented side.

' Example 3 A suitable solution for use in afllxing the above described pigmented layer to the cellulose ace-..

Per cent Acetone 75 Methyl alc ,Methyl Cellosolv e." i 10 The solution may be maintained in the applicator at approximately 75 F. by means such as hot water coil not shown. i g

The sheet I! now having the pigmented coating on one surface and a layer of penetrating solvent thereover continues its travel through the drying chamber 32 the atmosphere of which is maintained at about 150 F. In the course of this travel the solvent penetrates the pigmented layer land fcrms a tenacious bond between the cellulose acetate sheet and the pigmented coat- Methyl alcohol I Acetone ing. The solvent is then expelled from the sheet by the heat of the atmosphere in chamber 32 and the sheet may be further cured in chamber 52 where the atmosphere temperature-may be ap proximately 160 F.

Other suitable colored coatings which may be applied to a cellulose acetate sheet made of the composition disclosed in Example 1 are:

Example 4 Per cent Cellulose nitrate 2 Prussian hlue 2 Bu-tyl alcohni Methyl alcohol 15 Acetone- I 30 Methyl Cellosolve 16 Example 5 Cellulose acetate (acetyl content 30%) Titanox (Ti02) ,2 Butyl alcohol 35 Methyl alcohol 15 Acetm 1 g 30 Methyl Cellosolve 16 Asabove indicated" the base sheet I! may be Per cent 2 Ethyl alcohol 'Methyl Cellosolve by either of the pigmented solutions shown an anchoring tion:

Example 6 Per cent Acetone Ethyl alcohol 20 In some respects this solution 'is'moreTdeslrable than that disclosed in Example 3' but, however, the latter solution may also be employed.

I-have found by employing my novel process that the applied layers are more uniform in1thickv ness and have fewer smears or visual defects than;

if applied, as formerly, from solutions in. which the solvents were of a lower boiling type and had higher dissolving power for the base. They also have improved adherence and do not abrade.

easily. h

Thepigmented coatings in general result in placing a matte finish on the coated side of the sheet. However, if a smooth glossy surface is desired, a suitable filler ma be added to the 'anchoring solution. This can be done to any type of applied layer or anytype ofbase. An example of v such glossy overcoating is: a I

Example 7- Per cent Cellulose nitrate -o 2 70 Methyl alcnh nl 28 This coating will alsoserve as a protective layer for the underlying pigmented coating. If a matte protective overcoatingis desired /2% Titanox or other such pigmentmay be added to the composition shown in Example The process is also} applicable to applying a .dye or mixtures of dyes to various cellulose derivative-sheets. For example, if it is desired to apply a. cellulose acetate propionate overcoating to a cellulose acetate propionate sheet to which The'dyed surface of the sheet may beaflixed to the sheet and at the sametime coated with Ethylene dichloride 1 a protective layer such as:

made from other cellulose'derivatives. If the sheet has a cellulose nitrate base it may be coated Example 9 Per cent Cellulose acetate propionate 5 Ethylene chloride Acetone Ina similar manner a dye may be applied to a cellulose ether base sheeting. If a cellu-' lose ether sheet such as an ethyl cellulose sheet containing 48 to 50% ethoxy groups is to be dyed and a protective overcoating added, I may apply --the dye from the following solution:

Example 10 Zapon yellow 7 V Ethylene dichloride ...-30 Methyl alcohol 10 Benzene 10 in 1 Examples 2 and 4. In that case I may employ,

solution of the following composi- 7 Per cent This solvent is sufiicient to attach the dye looselyfto the surface of thebase. The dyed layer may be anchored to the base by an overcoating of the following solution:

Example 11 r Per cent Ethylene dichloride-.. '85 Methyl nlrnhnl 1O .Ethyl cellulose 5 -While the temperatures of the pigmented solutions and the anchoring or overcoating may vary somewhat with difierent compositions, in general the temperatures of the solution being applied'is within the range of 50 'to 70 F., and the tempera- ,ture of the surrounding atmosphere is from 130 to 160 F.

I claim: 1. The method of forming colored cellulose derivative sheeting which comprises coating the sheeting by applyingthereto a coloring material in a solvent which has only slight solvent action on the sheeting, drying the coating, and

fixing the coating to the sheeting by wetting the coated sheeting with a solvent which has solvent acetate sheeting which comprises applying to the sheeting a cellulose nitrate base coating containmg titanium dioxide in a solvent which has only slight solvent action on the sheeting, drying the coating, and fixing the coating to the sheeting by applying a solvent over .the coating which has a good solvent action upon both the sheeting and the coating.

8. The method of forming colored cellulose I acetate sheeting which comprises applying to the sheeting a cellulose nitrate base coating containing titaniumdioxide in a solvent which has only slight solvent action on the sheeting, drying the sheeting a cellulose nitrate base coating containfixing the coating to the sheeting by applying a solvent over the coating which penetrates the coating and has a good solvent action upon both the sheeting and the coating.

3. The method of forming colored cellulose derivative sheeting which comprises coating the sheeting by applying'thereto a coloring material in a solvent which has has only slight solvent action on the sheeting, drying the coating, and

protecting and fixing the coating to the sheeting by applying a cellulose ester solution over the coating, the solvent of which has good solvent action for the sheeting and the coating and the base of which covers the colored layer.

4. The method of iormingocolored cellulose derivative sheeting which comprises coating the sheeting by applying thereto a colored pigment in a solvent which has only 'slight solvent action on the sheeting, drying the coating, and fixing the coating to the sheeting by applying s01- coating and protecting and fixing the coating to the sheeting by applying a cellulose nitrate solution over the coating, the solvent of which has good solvent action for the sheeting nd the coat. ing and the cellulose nitrate base of which covers the titanium dioxidelayer.

9. The method of forming colored cellulose derivative sheeting which'comprises coating the sheeting by applying thereto a coloring material in a solvent mixture containing a high boiling solvent and having only slight solvent action on the sheeting, drying the coating, and fixing the coating to the sheeting by wetting the coated sheeting with a low boiling solvent which has solvent action for both the sheeting and the coating.

10. The method of forming colored cellulose ester sheeting which comprises applying to the ing titanium dioxide in a solvent mixture including a high boiling solvent, drying the coating, and fixing the coating to the sheeting by applying a low boiling solvent over the coating which has a good solvent action upon both the sheeting and coating.

11. The method of fonming' colo'red cellulose ester sheeting which comprises applying to'the sheeting acoating containing'a dye in a solvent mixture including a high boiling solvent, drying the coating, and fixing the coating to the sheeting by applying a low boiling solvent over the dyed coating. which has a'good solvent action up;-

on the sheeting and the coating.

12.-The continuous-method of forming colored cellulose derivative sheeting which comprises vent over the coating which has good solvent action for the sheeting and the pigmented coating. z

5.-The method'of iorming colored cellulose ester sheeting which comprises coating the sheeting by applying thereto a coloring material in continuously coating the sheeting by applying thereto a coloring material in a solvent which has moderate solvent action on .the sheeting, continuously drying the vcoating, fixing thecoating to the sheeting by-continuously wetting the coated sheeting with a solvent which has pronounced solvent action for both the sheeting and the coating whereby the coating is firmly attached to the sheeting and then again'drying the sheeting. t I

13. The continuous method of forming .colored a solvent which has only slight solvent action on the sheeting, drying the coating, and fixing the coating to the sheeting by applying a solvent for both the sheeting and the coating. I, I

6. The method of forming colored cellulose- ,over the coating which has good solvent action acetate sheeting which comprises coating "the sheeting'by applying theretqa coloring material containingtitanium dioxide in a solvent 50- lution which has only slight solvent action on the sheeting, drying the coating, and tilting the coating to the sheeting by applying a' solvent over the coating which has good solvent action for both the sheeting and the coating.

7. The method of ,forming colored cellulose cellulose derivative sheeting which comprises continuously coating the-sheeting/by applying, thereto a-coloring material in a solvent mixture containing a high boiling solvent having slight solvent action on the sheeting, whereby the coating is superficially attached to the sheeting 'con- Ttinuously drying the coating, and then fixing the coating to the sheeting by continuously wetting the coatedsheeting with a low boiling solvent which has active solvent action for both the sheeting and the coating whereby the coating is firmly attached to the sheeting and then contin-.

uously drying the sheeting.

' monies.- L. Pm, I 

